1. Field of the Invention
The invention relates to a keyboard apparatus used in electronic keyboard instruments such as an electronic organ, an electronic piano, and a synthesizer, or in electric keyboard instruments.
2. Description of the Related Art
Some of conventional keyboard apparatuses used in electronic keyboard instruments such as electronic organs and electronic pianos also include mass members generally called hammers in correspondence to respective keys, so as to provide a heavy touch feeling close to a key touch feeling of an acoustic musical instrument such as a piano. The hammers pivot in linkage with a key depression operation of the respective keys to give a force depending on their movement as a reactive force against a key depression force, thereby providing a desired key depression touch feeling.
For example, a keyboard apparatus disclosed in U.S. Pat. No. 5,834,668 B is structured such that keys and mass members extending under the keys along a key longitudinal direction are pivotably supported on a keyboard frame being a support member, and when the keys are depressed, the mass members are driven to pivot by force transmitting parts provided under the keys, and inertia moment generating parts in a metal bar-shape thereof are lifted with a large stroke to provide a heavy key touch feeling. When the keys are released, the mass members pivot in a reverse direction and the inertia moment generating parts return to a descended position.
In order to allow the inertia moment generating parts of the mass members to thus move up/down with a large stroke at the time of key depression/release, it is necessary for the support member to have a large space under the keys.
Further, in a case where the support member is formed of resin, ribs are formed for coupling support parts and reinforcing the whole support member. The ribs are arranged at intervals in an arrangement direction of the keys and the mass members to extend in parallel to the longitudinal direction of the keys and the mass members, and these ribs are provided also in the vicinity of a lower end of the support member.
Therefore, the space under the keys cannot be used effectively and in particular, does not allow long functional components and so on in the arrangement direction of the keys and the mass members (key width direction) to be disposed.